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Biomedical subjects

R Junges

Publications and source records attributed to R Junges.

8 recordsLinked to original sources
PubMed1985

[Effect of the method of measurement on the interpretation of renal clearance].

The concept of renal clearance measured during steady-state conditions includes the effect of filtration and secretion as well as urine flow. On the other hand, renal clearance, as used in nuclear medicine, only describes the effect of filtration and secretion. A way for determining steady-state renal clearance with a bolus injection technique is described. Steady-state renal clearance reflects the efficiency of filtration and secretion, urine flow, and the steady-state chemical potentials in the kidneys.

Humans↗
PubMed1984

[A new concept for detailed measuring of the excretory function of the kidney].

A new method to investigate renal function in detail without use of catheters is demonstrated. This method combines the advantages of two techniques, the physiological clearance measurement technique and the isotope nephrogram technique. The function of each kidney is quantitated in terms of the velocity of renal blood flow, the velocity of filtration and secretion and the velocity of urine flow to the bladder. The new concept is illustrated by two clinical examples.

Female↗
PubMed1983

Noise analysis and relaxation experiments of transport of hydrophobic anions across lipid membranes at equilibrium and nonequilibrium.

Under equilibrium and nonequilibrium steady-state conditions, the spectral intensity of current noise SJ(f) generated by the transport of hydrophobic anions across lipid bilayer membranes was investigated. The experimental results were compared with different reaction models. SJ(f) showed a characteristic increase proportional to f2 between frequency-independent tails at low and high frequencies. This gradient was found to be independent of applied voltage which indicates the contribution of a single voltage-dependent reaction step of ion translocation across the membrane. From the shape of SJ(f) at low frequencies the rate constant of ion desorption from the membrane into the aqueous phase could be estimated. Unambiguous evidence for the application of a general model, which includes the coupling of slow ion diffusion in the aqueous phase to ion adsorption/desorption at the membrane interface, could not be obtained from the low-frequency shape of SJ(f). The shot noise of this ion transport determines the amplitude of SJ(f) at high frequencies which decreases with increasing voltage applied. Analysis of voltage-jump current-relaxation experiments and of current noise carried out on one membrane yielded significant differences of the derived ion partition coefficient. This deviation is qualitatively described on the basis of incomplete reaction steps.

Anions↗
PubMed1983

[Direct and non-invasive determination of cardiac volume].

An improved isotope method for direct and non-invasive determination of heart volume, ejection volume and volume/time is described. By taking account of the reduction in the radio-active marker during the procedure, very good correlation of the results with those of cine ventriculography carried out at the same time can be expected.

Cardiac Output↗
PubMed1983

[Radionuclide determination of renal clearance equivalent to physiological clearance measurements].

The concept of renal clearance in nuclear medicine describes the tubular secretion and glomerular filtration of a substance being removed from the blood plasma. The concept of clearance as used physiologically is rather wider and includes consideration of the outflow of the substances remained back in the kidneys. The present paper discusses clearance measurements as seen from a thermo-dynamic point of view, in which isotope clearances become equivalent with the physiological concept of clearance. In addition, it is possible to quantify each single step of the excretory function of each kidney separately.

Child↗
PubMed1983

[A new nuclear medicine method for studying heart function without ECG-trigger and without the effect of body background radiation].

The intensity fluctuations of the radiation from a beating heart filled with radioactively labeled blood is analysed in such a way that the stroke volume and thus the cardiac output can be determined. The method is independent of any background radiation and irregularities of the heart rate. Further features are the speed of the method and the immediate imaging of the kinetics of the heart wall.

Heart↗
PubMed1981

[Results of computed tomography of the lumbar vertebral discs (author's transl)].

As shown in 150 patients, myelography and computed tomography (CT) lead to identical results in the investigation of vertebral disc lesions of the lower lumbar spine. In less severe disc changes, where myelography is not indicated, CT findings largely correspond with clinical findings. CT investigations are risk free, without side effects, painless, fast and economical.

Adolescent↗